Breakaway pipe coupling

ABSTRACT

A breakaway pipe coupling for coupling a pipeline together comprising a pair of telescopingly engaged upper and lower tubular coupling members adapted to be connected to a pipeline and including a pair of flanges surrounding the members for holding them in fixed relationship, one flange being secured to the upper coupling member and a split flange surrounding but not secured to the lower coupling member. Frangible bolts secure the upper flange portion to the split flange with the split flange adapted to separate when undue stress is placed on the coupling members and breaks the frangible bolts.

United States. Patent Kubasta [451 May 2, 1972 s41 BREAKAWAYPIPECOUPLING 925,770 6/1909 Herrick ..285/368 2,83l,708 4/1958 Kircher..285/368 [72] Inventor. James W. Kulmta, Metame, La. 2,712,438 7/1955Brown Jr".- umzss/sas x {73] Assignee: Shell Oil Company, New York, N.Y.3, 10,995 1 H1968 Gray ..285/2 X [22] Filed: 1970 PrimaryExaminer-Andrew V. Kundrat [2]] Appl No 71,528 Attorney-George G.Pritzker and Harold L. Denkler I 57 ABSTRACT [52] U.S.CI...285/3,285/368,285/4l2 I I s11 rm. Cl. .narss/oo A P'P ""8 9 'P'"'wwhef 5s Fleld ofSearch ..2ss/2, 3,4, 368, 356, 387, a P elemPmglY and285/4|2 tubular coupling members adapted to be connected to a pipelineand including a pair of flanges surrounding the mem- [56] Rdeunces cmdbers for holding them in fixed relationship. one flange being secured tothe upper coupling member and a split flange sur- Nn-E STATES PATENTSrounding but not secured to the lower coupling member. Frangible boltssecure the upper flange portion to the split 1,309,146 7/l9l9 Mann"285/368 flange with the split flange adapted to separate h undue gistress is placed on the coupling members and breaks the """P fran ibleblts.

602,378 4/1898 Thomson... 8 o 1.525.647 2/1925 Haughey ..28 5/368 X9Clalms, 3 Drawing Figures f I I- H Patented May 2, 1972 3,659,877

2 Sheets-Sheet l INVENTOR. JAMES w. KUBASTA F IG l BY ATTORNEY BREAKAWAYPIPE COUPLING BACKGROUND OF THE INVENTION 1. Field of the Invention Theinvention relates to pipe couplings; and, more particularly, to abreakaway pipeline coupling which is adapted to separate and fall offthe pipe when undue stress is placed thereon.

2. Description of the Prior Art It is well known that a pair ofpipelines may be coupled together in a fluid-tight manner by means ofcouplings or the like. Such couplings generally involve providingflanges or the like on each pipeline, then securing the flangestogether.

However, such procedures have proven unsatisfactory where the cost ofequipment associated with the pipeline is relatively high with respectto the pipeline or couplings themselves and when the pipelines aresubjected to external stresses, such as when laid underwater. Forexample, should undue stress be placed on the pipeline, equipment willbe damaged until the pipelines separate. Thus, a pipeline couplingassembly is required that will part before other, and possibly moreexpensive, apparatus connected to the pipeline fails.

SUMMARY OF THE INVENTION It is an object of this invention to provide apipe coupling which is adapted to break when subject to undue stress.

It is a further object of this invention to provide a bolted flange forjoining the coupling whereby, when subject to undue stress, the boltswill separate and the flange can fall off the pipe coupling permittingthe pipe to pass through a conduit of smaller internal diameter than theouter diameter of the flange and without damaging equipment associatedwith one or both ends of the pipeline.

These and other objects are preferably accomplished by providing a pairof telescopingly engaged upper and lower tubular coupling membersadapted to be connected to a pipeline and a pair of upper and lowerflanges surrounding the couplings for holding them in fixedrelationship, the upper flange being secured to the upper couplingmember and a split flange surrounding the lower coupling member.Frangible bolts secure the upper flange portion to the split flange withthe split flange adapted to separate and fall off the coupling whenundue stress is placed on the coupling members. This coupling may beplaced immediately above an underwater pipeline riser conduit. The splitlower flange will allow the parted pipeline coupling to move through theconduit should it be pulled by some foreign object at the sea floor.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a vertical view of onepossible installation of a pipeline coupling in accordance with theteaching of my invention;

FIG. 2 is a vertical, partly sectional view of the pipe coupling; and

FIG. 3 is a full elevational view of the split flange of the coupling ofFIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT above the riser conduit 102. Thesection 15 of the pipeline above the coupling is rigidly connected atbrace 112 to the platform 104. The lower section 13 of the pipelinebelow the coupling 10 passes through the conduit 102 but is notsecuredto it. Thus, when anexternal force such as from shifting soils on theocean bottom 106 or from a boat anchor (not shown) is applied topipeline 101, the coupling 10 will part and the split flange 35, as willbe discussed further hereinbelow, will be pulled down with the lowersection 13 of the pipeline 101 until the thick section 46 of the splitflange 35 contacts the top of the conduit 102. The jolt from this impactwill cause the thin section 47 of the splitflange 35 to continue fallingsuch that it will unkey itself from the thick section 46 and both halves46 and 47 of-the split flange 35 may then fall ofl coupling 10permitting the lower section 13 pipeline 101 to continue passing throughconduit 102. This will remove the loading from the conduit bracing 103which had been transmitted into the platform bracing 108 thus subjectingthem to potential failure.

Referring now to FIG. 2 of the drawing, pipe coupling 10 is shown indetail as having a lower generally tubular hollow male coupling member11 telescopingly fitting into an upper generally tubular hollow femalecoupling member 12. Coupling member 11 is adapted-to be secured to thelower section 13 of the pipeline 101, as by welding 14, whereas couplingmember 12 is adapted to be secured to the upper section 15 of pipeline101, as by welding 16. In this manner, fluids may be flown withinsection 13 of pipeline 101 past coupling 10 and through section 15, orvice versa,

Preferably, as shown in FIG. 2, lower coupling member 11 includesbearing means extending about its outer surface, such as raised annularring 17, for reasons to be discussed further hereinbelow. Upper couplingmember 12 preferably includes a first generally vertical portion 18 ofan inner diameter approximately the same as the inner diameter of lowercoupling member 11 and pipeline sections 13 and 15. Portion 18 thenextends generally downwardly and outwardly, as at second portion 19,then downwardly substantially vertically to form a third portion 20.Portion 20 forms an annular space 21 between it and the outer wall oflower coupling member 11. One or more apertures 22 are formed in portion20 for receiving set screws 23 or the like therein for securing retainerring 24 for reasons to be discussed further hereinbelow. These setscrews may be disposed about the outer surface of portion 20, as forexample, every or so.

The substantially cylindrical retainer ring 24 is disposed in annularspace 21, the ring 24 having threads 25 or the like at its lower endadapted to engage threads 26 on the lower end of the third portion 20 ofupper coupling member 12. Set screws 23 in portion 20 thus contactretainer ring 24 and secure it from being screwed out. Sealing means,such as a plurality of spacer or packing rings 27 are disposed above theupper surface 28 of retainer ring 24 and below an abutment surface 29 onthird portion 20 extending inwardly therefrom generally horizontallytoward the central longitudinal axis of pipe coupling 10. In thismanner, with threads 25 and 26 engaged and set screws 23 tightenedagainst ring 24, a fluid-tight seal is formed between the engagement oflower and upper coupling members 11 and 12.

An upper flange member 30 is provided encircling the upper couplingmember 12. Flange member 30 includes a plurality of apertures 32extending therethrough, only one being shown in FIG. 1 for convenienceof illustration. At its point of engagement with the third portion 20 ofthe upper coupling member 12, flange portion 30 preferably is beveled topoint 33. Upper flange member 30 may then be secured to third portion 20by welding in the spaces 34 formed above and below point 33 as shown inFIG. 1. In this manner, the upper flange member 30 is fixedly secured tothe upper coupling member 12.

Furthermore, a lower split flange portion 35 (see also FIG. 3) isprovided encircling the lower coupling member 11. Flange portion 35includes a bearing surface 36 thereon at its point of engagement withlower coupling member 11, the surface 36 conforming to ring 17 in amanner such that movement downward of ring 17 is prevented by surface36. In this manner, also, that is, by means of the engagement of surface38 and the face 37 of portion 20, a space 53 is formed between the upperand lower flange portions 30 and 35 as can be seen in FIG. 2.

A plurality of apertures 39 are formed in lower flange portion 35similar to and aligned with apertures 32 on upper flange portion 30.Apertures 39 preferably include enlarged aperture portions 40 forreceiving one or more nuts or the like. Thus, securing means areprovided between upper and lower flange portions and by extending bolts41 or the like through apertures 32 and 39. Bolts 41 are preferablythreaded at each end so as to receive a lock nut 42 at one end and a jamnut 43 and lock nut 44 at the other end. As can be seen in FIG. 1, jamand lock nuts 43 and 44 are disposed in aperture portion on lower flangeportion 35. However, obviously similar arrangements may be provided forfastening together the upper and lower flange portions 30 and 35.However, in whatever arrangement is used, the bolt 41 or the like mustbe frangible in the manner to be discussed further hereinbelow.

Thus, bolt 41 preferably includes a central reduced portion which isadapted to part when undue stress is put thereon. For example, l2-inchbolts of titanium or the like may be used with the bolts having athickness at its greatest shaft diameter of approximately 1 inch and areduced neck at portion 45 of approximately three-quarters of an inch.Regardless of the materials or dimensions used, bolts 41 are designed topart at a predetermined load.

Referring now to FIG. 3, the split flange portion 35 is shown in detail.Split flange portion 35 comprises a pair of half-rings 46 and 47, one ofthe rings, such as ring 46, being substantially thicker in cross-sectionthan the other. Ring 46 also includes a generally horizontally extendingportion 48 having a generally downwardly extending lip portion 49'adapted to mate with a like generally horizontally extending portion andgenerally upwardly extending lip portion 51 thereon in the mannerillustrated in F IG. 3. Thus, the abutting engagement of lip portions 49and 51 prohibits lateral separation of rings 46 and 47 while permittingdownward movement and separation thereof. An aperture 52 (shown indotted lines) is formed by the mating engagement of rings 46 and 47 forreceiving lower coupling member 11 therein.

ln operation, the packing rings 27 are inserted into upper coupling 12.The retainer ring 24 is then made up by means of threads 25 and 26 inupper coupling 12 and the set screws 23 are tightened to preventretainer ring 24 from backing 05. Lower coupling 11 is then insertedinto upper coupling 12 containing packing rings 27 which provide afluid-tight seal between coupling members 11 and 12. The upper flangemember 30 is disposed about portion 20 on upper coupling member 12 andwelded thereto, as in spaces 34 adjacent to point 33 and the lower endof portion 20. In this manner, flange portion 30 is fixed to the uppercoupling member 12.

The lower flange portion 35, which includes mating halfrings 46 and 47,is now disposed about the lower coupling member 11. The ring 17 onmember 1 1 contacts surface 36 on split flange 35 while surface 38 ofmember 11 contacts surface 37 of member 12. Frangible bolts 41 are nowplaced in the aligned apertures 32 and 39 in upper and lower flangeportions 30 and 35, respectively. Lock nuts 42 are secured to the upperends of bolts 41 and jam nuts 43 and lock nuts 44 are secured to thelower end of bolts 41, nuts 43 and 44 being located in the apertureportions 40 of split flange portion 35.

Pipeline sections 13 and 15 are now secured to the free ends of lowercoupling member 11 and upper coupling member 12, respectively.

it is to be understood that pipeline sections 13 and 15 are coupled tosuitable equipment associated with such pipeline sections. Should unduestress be placed on section pipeline 13, such stress will be transmittedto coupling 10. In order to prevent damage to other and possibly moreexpensive equipment associated with pipeline sections 13 and 15, bolts41 part at their reduced portions 45 and the half-rings 46 and 47 oflower split flange portion 35 separate. Flange portion 35, now no longerattached to the upper flange portion 31, drops off and lower couplingmember 11 separates from upper coupling member 12. The pipeline section13, now separated from pipeline section 15 and having only lowercoupling member 11 attached thereto, may pass without damage throughother equipment associated with pipeline sections 13 and 15, as forexample, a pipeline riser conduit or the like associated with the layingof pipelines underwater as shown in F IG. 1.

Thus, although the invention has been described as applicable to thecoupling of any pipelines, it is particularly applicable to the layingof pipelines underwater where the pipelines are subjected to unduestresses from unstable soil conditions or anchors from large marinevessels.

I claim as my invention:

1. A breakaway pipe coupling for coupling a pipeline togethercomprising:

a first longitudinally extending open-ended generally tubular couplingmember having a bearing ring thereon;

a second longitudinally extending open-ended generally tubular couplingmember telescopingly fitting over one of the ends of said first couplingmember and including sealing means thereon for maintaining said couplingmembers in fluid-tight relationship;

flange means surrounding said first and second coupling means forholding said first and second coupling members in fixed relationship;

said flange means including an upper flange portion encircling saidsecond coupling member and secured thereto and a mating lower flangeportion encircling said first coupling member;

said lower flange portion comprising a pair of split ring portionshaving interlocking engagement means disposed on the abutting endportions of said pair of split rings, said engagement means preventinglateral movement of said split rings while pennitting axialdisengagement of said split rings;

said pair of split rings in addition having a bearing surface formedthereon and disposed to engage the bearing ring on said first couplingmeans to prevent axial movement of said first coupling means in at leastone direction;

one of said ring members in addition having a greater axial thicknessthan the other of said ring members, said difference in thickness beingsufficient to permit said engagement means to be disengaged when saidone ring member contacts an axial stop; and

frangible securing means connected to each of said flange portions forsecuring said flange portions together until the frangible limit of saidsecuring means is reached whereby said engagement means on said ringmembers may be disengaged and said ring members separate and drop off ofsaid first coupling member.

2, The coupling of claim 1 wherein said bearing ring is a rib extendingcircumferentially of said first coupling member.

3. The coupling of claim 1 wherein said second coupling member includesa downwardly extending offset portion thereon and said first couplingmember telescopingly fits into said offset portion in a manner formingan annular space between said offset portion and said first couplingmember, said offset portion being threaded on a threaded portion thereofinternally of said second coupling member; and

said sealing means includes an annular ring disposed in said annularspace in threading engagement with said threaded portion, said sealingmeans further including packing means disposed between said annular ringand both said coupling members for sealing said coupling members in afluid-tight manner.

4. The coupling of claim 3 wherein said offset portion includes aplurality of apertures therein extending circumferentially of saidoffset portion; and

set screw means disposed in said oifset portion apertures adapted toengage said annular ring and thus secure said annular ring to saidoffset portion.

5. The coupling of claim 1 wherein said split ring portions comprise apair of interlocking half-rings partially encircling said first couplingmember, one of said half-rings having a first generally horizontallyextending portion with a generally vertically downwardly extending lipportion at its outer end and the other of said half-rings having a firstgenerally horizontally extending portion with a generally verticallyupwardly extending lip portion at its outer end, each of said lipportions interlocking in a manner preventing lateral movement of saidhalfrings but permitting vertical disengagement thereof.

6. The coupling of claim 1 wherein said frangible securing meansincludes a plurality of frangible bolts securing said flange portionstogether.

7. The coupling of claim 6 wherein each of said frangible bolts includea reduced diameter shank portion.

8. The coupling of claim 7 wherein said bearing means on said lowerflange portion engages said bearing ring on said first coupling memberin a manner forming a space between said upper coupling member and saidlower flange portion.

9. The coupling of claim 8 wherein said bolts are threaded at both ends;

threaded nuts threaded on one end of each of said bolts and abuttingagainst the upper face of said upper flange portion; and second threadednuts threaded on the other end of each of said bolts, said second nutsbeing disposed in an annular cavity formed in the lower flange portionand thus securing said lower flange portion to said upper flangeportion.

1. A breakaway pipe coupling for coupling a pipeline togethercomprising: a first longitudinally extending open-ended generallytubular coupling member having a bearing ring thereon; a secondlongitudinally extending open-ended generally tubular coupling membertelescopingly fitting over one of the ends of said first coupling memberand including sealing means thereon for maintaining said couplingmembers in fluid-tight relationship; flange means surrounding said firstand second coupling means for holding said first and second couplingmembers in fixed relationship; said flange means including an upperflange portion encircling said second coupling member and securedthereto and a mating lower flange portion encircling said first couplingmember; said lower flange portion comprising a pair of split ringportions having interlocking engagement means disposed on the abuttingend portions of said pair of split rings, said engagement meanspreventing lateral movement of said split rings while permitting axialdisengagement of said split rings; said pair of split rings in additionhaving a bearing surface formed thereon and disposed to engage thebearing ring on said first coupling means to prevent axial movement ofsaid first coupling means in at least one direction; one of said ringmembers in addition having a greater axial thickness than the other ofsaid ring members, said difference in thickness being sufficient topermit said engagement means to be disengaged when said one ring membercontacts an axial stop; and frangible securing means connected to eachof said flange portions for securing said flange portions together untilthe frangible limit of said securing means is reached whereby saidengagement means on said ring members may be disengaged and said ringmembers separate and drop off of said first coupling member.
 2. Thecoupling of claim 1 wherein said bearing ring is a rib extendingcircumferentially of said first coupling member.
 3. The coupling ofclaim 1 wherein said second coupling member includes a downwardlyextending offset portion thereon and said first coupling membertelescopingly fits into said offset portion in a manner forming anannular space between said offset portion and said first couplingmember, said offset portion being threaded on a threaded portion thereofinternally of said second coupling member; and said sealing meansincludes an annular ring disposed in said annular space in threadingengagement with said threaded portion, said sealing means furtherincluding packing means disposed between said annular ring and both saidcoupling members for sealing said coupling members in a fluid-tightmanner.
 4. The coupling of claim 3 wherein said offset portion includesa plurality of apertures therein extending circumferentially of saidoffset portion; and set screw means disposed in said offset portionapertures adapted to engage said annular ring and thus secure saidannular ring to said offset portion.
 5. The coupling of claim 1 whereinsaid split ring portions comprise a pair of interlocking half-ringspartially encircling said first coupling member, one of said half-ringshaving a first generally horizontally extending portion with a generallyvertically downwardly extending lip portion at its outer end and theother of said half-rings having a first generally horizontally extendingportion with a generally vertically upwardly extending lip portion atits outer end, each of said lip portions interlocking in a mannerpreventing lateral movement of said half-rings but permitting verticaldisengagement thereof.
 6. The coupling of claim 1 wherein said frangiblesecuring means includes a plurality of frangible bolts securing saidflange portions together.
 7. The coupling of claim 6 wherein each ofsaid frangible bolts include a reduced diameter shank portion.
 8. Thecoupling of claim 7 wherein said bearing means on said lower flangeportion engages said bearing ring on said first coupling member in amanner forming a space between said upper coupling member and said lowerflange portion.
 9. The coupling of claim 8 wherein said bolts arethreaded at both ends; threaded nuts threaded on one end of each of saidbolts and abutting against the upper face of said upper flange portion;and second threaded nuts threaded on the other end of each of saidbolts, said second nuts being disposed in an annular cavity formed inthe lower flange portion and thus securing said lower flange portion tosaid upper flange portion.